Finding the Fourth Proportional to 3,105.20, 4,199.70 and 3,105.20

Step by Step Solution

1. Step 1: Write the proportion equation
   3,105.20 : 4,199.70 = 3,105.20 : x
2. Step 2: Convert to fraction form
   3,105.20/4,199.70 = 3,105.20/x
3. Step 3: Cross multiply
   3,105.20x = 4,199.70 × 3,105.20
4. Step 4: Simplify right side
   3,105.20x = 13,040,908.44
5. Step 5: Solve for x
   x = 13,040,908.44/3,105.20
6. Step 6: Final answer
   x = 4,199.70